磁盘突发Disk bursting

在 Azure 上,我们提供了在虚拟机和磁盘上提升磁盘存储 IOPS 和 MB/秒性能的功能(称为突发)。On Azure, we offer the ability to boost disk storage IOPS and MB/s performance referred to as bursting on both Virtual Machines and disks. 突发在许多情况下很有用,例如处理意外的磁盘流量或处理批处理作业。Busting is useful in many scenarios, such as handling unexpected disk traffic or processing batch jobs. 可以有效地利用 VM 和磁盘级别的突发,以在 VM 和磁盘上实现良好的基线性能和突发性能。You can effectively leverage VM and disk level bursting to achieve great baseline and bursting performance on both your VM and disk. 这样,你就可以在 VM 和磁盘上都获得良好的基线性能和突发性能。This way you can achieve great baseline performance and bursting performance on both your vm and disk.

请注意,磁盘和 VM 上的突发相互独立。Please note that bursting on Disks and VMs are independent from one another. 如果有突发磁盘,则不需要使用突发 VM 来允许磁盘突发。If you have a bursting disk, you do not need a bursting VM to allow your disk to burst. 如果有突发 VM,则不需要使用突发磁盘来允许 VM 突发。If you have a bursting VM, you do no need a bursting disk to allow your VM to burst.

磁盘级别突发Disk level bursting

对于所有区域中大小为 P20 和更小的磁盘,在我们的高级 SSD 上也提供了突发功能。Bursting is also available on our premium SSDs for disk sizes P20 and smaller in all regions. 在支持磁盘突发的磁盘大小的新部署上,默认已启用磁盘突发。Disk bursting is enabled by default on new deployments of the disk sizes that support it. 支持磁盘突发的现有磁盘大小可以通过以下任一方法启用突发:Existing disk sizes, if they support disk bursting, can enable bursting through either of the following methods:

  • 重启 VMRestart the VM
  • 分离再重新附加磁盘Detach and reattach the disk

常见场景Common scenarios

以下需求场景可显著受益于突发:The following scenarios can benefit greatly from bursting:

  • 缩短启动时间 - 在使用突发的情况下,实例的启动速度将大大加快。Improving boot times - With bursting, your instance will boot at a significantly faster rate. 例如,启用高级层的 VM 的默认 OS 磁盘是 P4 磁盘,其预配性能最高可达 120 IOPS 和 25 MB/s。For example, the default OS disk for premium enabled VMs is the P4 disk, which is a provisioned performance of up to 120 IOPS and 25 MB/s. 在使用突发的情况下,P4 的性能最高可达 3500 IOPS 和 170 MB/s,可使启动速度加快 6 倍。With bursting, the P4 can go up to 3500 IOPS and 170 MB/s allowing for a boot time to accelerate by 6X.
  • 处理批处理作业 - 某些应用程序的工作负荷是周期性的,在大部分时间内需要基线性能,仅在很短的时间段内需要较高的性能。Handling batch jobs - Some application's workloads are cyclical in nature and require a baseline performance for most of the time and require higher performance for a short period of time. 这种情况的一个示例是一个会计程序,该程序每日处理需要少量磁盘流量的事务。An example of this is an accounting program that process transactions daily that require a small amount of disk traffic. 然后,在月末,该程序将运行需要大量磁盘流量的对帐报表。Then at the end of the month, does reconciling reports that need a much higher amount of disk traffic.
  • 为流量高峰做准备 - Web 服务器及其应用程序随时都可能遇到流量激增。Preparedness for traffic spikes - Web servers and their applications can experience traffic surges at any time. 如果 Web 服务器由使用突发的 VM 或磁盘提供支持,那么这些服务器便可以更好地处理流量高峰。If your web server is backed by VMs or disks using bursting, the servers are better equipped to handle traffic spikes.

突发流Bursting flow

突发额度系统以相同的方式应用于虚拟机级别和磁盘级别。The bursting credit system applies in the same manner at both the virtual machine level and disk level. 你的资源(VM 或磁盘)将从充分储备的额度开始。Your resource, either a VM or disk, will start with fully stocked credits. 有了这些额度,便能够以最大的突发速率进行 30 分钟的突发。These credits will allow you to burst for 30 minutes at the maximum burst rate. 当资源在其性能磁盘存储限制下运行时,突发额度会进行累积。Bursting credits accumulate when your resource is running under their performance disk storage limits. 如果资源使用的所有 IOPS 和 MB/s 低于性能限制,额度将开始累积。For all IOPS and MB/s that your resource is using below the performance limit you begin to accumulate credits. 如果资源已经积累了要用于突发的额度,并且你的工作负荷需要额外的性能,则资源可以使用这些额度超出你的性能限制,为工作负荷提供所需的磁盘 IO 性能以满足其需求。If your resource has accrued credits to use for bursting and your workload needs the extra performance, your resource can use those credits to go above your performance limit to give it the disk IO performance it needs to meet the demand.

突发桶关系图

有关突发累积,需要注意的一件事是,各个资源的突发累积都各不相同,因为它基于资源在其性能限制下运行时未使用的 IOPS 和 MB/s。One thing to note about burst accumulation is that it is different for each resource since it is based on the unused IOPS and MB/s below their performance amounts. 这意味着,较高基线性能的产品积累其突发额度的速度可能会快于较低基线性能的产品。This means that higher baseline performance products can accrue their bursting amounts faster than lower baseline performing products. 例如,处于空闲状态、没有任何活动的 P1 磁盘将每秒积累 120 IOPS,而 P20 磁盘在处于空闲状态、没有任何活动时将每秒积累 2300 IOPS。For example, a P1 disk idling with no activity will accrue 120 IOPS per second whereas a P20 disk accrues 2,300 IOPS per second while idling with no activity.

突发状态Bursting states

启用了突发功能时,资源可能处于以下三种状态之一:There are three states your resource can be in with bursting enabled:

  • 正在积累 - 资源正在使用的 IO 流量低于性能目标。Accruing - The resource's IO traffic is using less than the performance target. 为 IOPS 和 MB/s 累积额度是彼此分开执行的。Accumulating bursting credits for IOPS and MB/s are done separate from one another. 你的资源可能会积累 IOPS 额度并支出 MB/s 额度,也可能会支出 IOPS 额度并积累 MB/s 额度。Your resource can be accruing IOPS credits and spending MB/s credits or vice versa.
  • 正在突发 - 资源正在使用的流量高于性能目标。Bursting - The resource's traffic is using more than the performance target. 突发流量将独立消耗 IOPS 或带宽的额度。The burst traffic will independently consume credits from IOPS or bandwidth.
  • 恒定 - 资源的流量与性能目标完全相同。Constant - The resource's traffic is exactly at the performance target.

有关突发的示例Examples of bursting

以下示例显示了在使用各种虚拟机和磁盘组合时突发的工作情况。The following examples show how bursting works with various virtual machine and disk combinations. 为了使示例易于理解,我们将重点放在 MB/s 上,但相同的逻辑也独立适用于 IOPS。To make the examples easy to follow, we will focus on MB/s, but the same logic is applied independently to IOPS.

具有可突发磁盘的非可突发虚拟机Non-burstable virtual machine with burstable Disks

VM 和磁盘组合:VM and disk combination:

  • Standard_D8s_v3Standard_D8s_v3

    • 未缓存的 MB/s:192Uncached MB/s: 192
  • P4 OS 磁盘P4 OS Disk

    • 预配的 MB/s:25Provisioned MB/s: 25
    • 最大突发 MB/s:170Max burst MB/s: 170
  • 2 个 P10 数据磁盘2 P10 Data Disks

    • 预配的 MB/s:25Provisioned MB/s: 25
    • 最大突发 MB/s:170Max burst MB/s: 170

当 VM 启动时,它将从 OS 磁盘中检索数据。When the VM boots up it will retrieve data from the OS disk. 由于 OS 磁盘是正在启动的 VM 的一部分,因此 OS 磁盘的突发额度将是充分的。Since the OS disk is part of a VM that is getting started, the OS disk will be full of bursting credits. 这些额度使 OS 磁盘以 170 MB/s 的速度突发启动,如下所示:These credits will allow the OS disk burst its startup at 170 MB/s second as seen below:

非突发 VM - 突发磁盘启动

启动完成后,应用程序将在 VM 上运行,并且具有非关键工作负荷。After the boot up is complete, an application is then run on the VM and has a non-critical workload. 此工作负荷需要 15 MB/S(在所有磁盘上均匀分布):This workload requires 15 MB/S that gets spread evenly across all the disks:

非突发 VM - 突发磁盘空闲

然后,应用程序需要处理一个批处理作业,该作业需要 192 MB/s。Then the application needs to process a batched job that requires 192 MB/s. 2 MB/s 由 OS 磁盘使用,其余部分在数据磁盘之间平均划分:2 MB/s are used by the OS Disk and the rest are evenly split between the data disks:

非突发 VM - 突发磁盘发生突发

具有非可突发磁盘的可突发虚拟机Burstable virtual machine with non-burstable disks

VM 和磁盘组合:VM and disk combination:

  • Standard_L8s_v2Standard_L8s_v2
    • 未缓存的 MB/s:160Uncached MB/s: 160
    • 最大突发 MB/s:1280Max burst MB/s: 1,280
  • P50 OS 磁盘P50 OS Disk
    • 预配的 MB/s:250Provisioned MB/s: 250
  • 2 个 P10 数据磁盘2 P10 Data Disks
    • 预配的 MB/s:250Provisioned MB/s: 250

初始启动后,应用程序将在 VM 上运行,并且具有非关键工作负荷。After the initial boot up, an application is run on the VM and has a non-critical workload. 此工作负荷需要 30 MB/S(在所有磁盘上均匀分布):突发 VM - 非突发磁盘空闲This workload requires 30 MB/s that gets spread evenly across all the disks: Bursting vm non-bursting disk idle

然后,应用程序需要处理一个批处理作业,该作业需要 600 MB/s。Then the application needs to process a batched job that requires 600 MB/s. Standard_L8s_v2 将发生突发以满足这一需求,然后,对磁盘的请求会均匀分布到 P50 磁盘:The Standard_L8s_v2 bursts to meet this demand and then requests to the disks get evenly spread out to P50 disks:

突发 VM - 非突发磁盘发生突发

具有可突发磁盘的可突发虚拟机Burstable virtual machine with burstable Disks

VM 和磁盘组合:VM and disk combination:

  • Standard_L8s_v2Standard_L8s_v2
    • 未缓存的 MB/s:160Uncached MB/s: 160
    • 最大突发 MB/s:1280Max burst MB/s: 1,280
  • P4 OS 磁盘P4 OS Disk
    • 预配的 MB/s:25Provisioned MB/s: 25
    • 最大突发 MB/s:170Max burst MB/s: 170
  • 2 个 P4 数据磁盘2 P4 Data Disks
    • 预配的 MB/s:25Provisioned MB/s: 25
    • 最大突发 MB/s:170Max burst MB/s: 170

VM 启动时,它将发生突发,从 OS 磁盘请求 1280 MB/s(其突发上限),OS 磁盘将以其 170 MB/s 的突发性能作为响应:When the VM boots up, it will burst to request its burst limit of 1,280 MB/s from the OS disk and the OS disk will respond with its burst performance of 170 MB/s:

突发 VM - 突发磁盘启动

启动完成后,应用程序将在 VM 上运行。Then after the boot up is complete, an application is then run on the VM. 应用程序具有一个非关键工作负荷,该工作负荷需要 15 MB/s(均匀分布到所有磁盘):The application has a non-critical workload that requires 15 MB/s that gets spread evenly across all the disks:

突发 VM - 突发磁盘空闲

然后,应用程序需要处理一个批处理作业,该作业需要 360 MB/s。Then the application needs to process a batched job that requires 360 MB/s. Standard_L8s_v2 发生突发以满足此要求,然后进行请求。The Standard_L8s_v2 bursts to meet this demand and then requests. OS 磁盘只需要 20 MB/s。Only 20 MB/s are needed by the OS disk. 剩余的 340 MB/s 由突发 P4 数据磁盘处理:The remaining 340 MB/s are handled by the bursting P4 data disks:

突发 VM - 突发磁盘发生突发